Tapping the supercapacitive properties of porous activated carbon from expired white chickpeas

Abstract

With an insight of clean and sustainable energy from green renewable waste, porous activated carbon was prepared by direct carbonization and activation of expired dried chickpeas with ZnCl2 for supercapacitor application. The expired chickpeas were powdered and mixed with zinc chloride in different ratios and pyrolyzed at high temperatures and the structural, morphological, and electrochemical analysis were studied. The pore size distribution of the carbonized samples was dominated by micropores and mesopores, with specific surface area in the range of 865.002 m2/g to 1094.638 m2/g and pore volume in the range of 0.618 cc/g to 0.739 cc/g. The as-fabricated symmetric device exhibited a specific capacitance of 204.6 F/g at 5 mV/s, the energy density of 11.732 Wh/kg and power density of 266.196 W/kg at 1 A/g with a capacitive retention of 97.48 % for 3000 cycles. Thus, the heterogeneous porous structure and excellent surface area helps in boosting the electrochemical behaviour of the expired white chickpea as waste derived carbon samples.